On Thu, 10 Feb 2022 at 20:29, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > (cc Kees) > ... for real this time :-) > On Thu, 10 Feb 2022 at 18:36, Victor Erminpour > <victor.erminpour@xxxxxxxxxx> wrote: > > > > > > On 2/10/22 1:11 AM, Ard Biesheuvel wrote: > > > On Thu, 10 Feb 2022 at 01:34, Victor Erminpour > > > <victor.erminpour@xxxxxxxxxx> wrote: > > >> When building with automatic stack variable initialization, GCC 12 > > >> complains about variables defined outside of switch case statements. > > >> Move the variable into the case that uses it, which silences the warning: > > >> > > >> ./drivers/acpi/arm64/iort.c:1670:59: error: statement will never be executed [-Werror=switch-unreachable] > > >> 1670 | struct acpi_iort_named_component *ncomp; > > >> | ^~~~~ > > >> > > >> Signed-off-by: Victor Erminpour <victor.erminpour@xxxxxxxxxx> > > > GCC 12 is not released yet, and this is clearly a compiler bug (a > > > declaration is not a statement, and the hidden offending statement > > > [the zero-init] is emitted by the compiler itself), so please report > > > this to the GCC folks instead. > > > > Hi Ard, > > > > Thanks for the reply. > > This fix is similar to the following commits that have been integrated > > upstream: > > https://lore.kernel.org/linux-hardening/20211209043456.1377875-1-keescook@xxxxxxxxxxxx/ > > https://lore.kernel.org/linux-hardening/20211209043915.1378393-1-keescook@xxxxxxxxxxxx/ > > > > If GCC 12 rejects valid C with this feature enabled, the compiler is > broken and needs to be fixed. Papering over this by making changes to > perfectly valid C code is a slippery slope that we should avoid. > > Since GCC 12 is not released yet, there is time to get this fixed properly. > > > You're not obligated to integrate this commit, > > Why, thank you :-) > > > but you may run into this > > issue once > > upstream starts using GCC 12 (or a patched version of GCC 11 in my case) > > with the > > CONFIG_INIT_STACK_ALL_ZERO option enabled. > > > > Yes, that part was perfectly clear.
